MHD instabilities at the disk-magnetosphere boundary: 3D simulations

摘要

We present results of 3D simulations of MHD instabilities at the accretion disk-magnetosphere boundary. The instability is Rayleigh-Taylor, and develops for a large range ofparameter values. It manifests itself in the form of tall, thin tongues of plasma that reach the starby penetrating through the magnetosphere in the equatorial plane. The tongues rotate aroundthe star in the equatorial plane, and their shape and number changes with time on inner-diskdynamical timescales. In contrast with funnel flows, which deposit matter mainly in the polarregion, the tongues deposit matter much closer to the stellar equator.